Sod is ordinarily cut from a field in which grass has been grown for that purpose, in six foot lengths that are eighteen inches wide and vary in thickness dependent upon the growth of grass there is on the sod being cut. Ordinarily this thickness will be approximately one inch. The rolls of sod weigh between forty and fifty pounds. The cutting of the sod in the field is principally a manual operation and the dimensions hereinbefore given are accordingly somewhat approximate and slightly variable. Recently it has become desirable to sod much larger areas than has been previously the case, because much of the sod laying is done over large areas such as highway embankments, that have a slope such that the seeding of these areas is either impractical or unsuccessful. The laying of sod has been principally a manual operation, which consumes considerable amount of time, where large areas have to be sodded.
It is accordingly a purpose of our invention to provide a machine that will lay a plurality of lengths of sod side by side and edge to edge simultaneously and which can be operated so that the relatively short lengths of sod can be laid with the trailing edges of one length in abutting relation to the leading edge of the next length that is being laid. Our machine is capable of doing this by proper operation thereof in spite of small variations in the length, width and thickness of sod strips that are being laid.
While artificial turf has come into use for athletic fields and similar places, and apparatus has been provided for not only laying the artificial turf but also taking it up and cleaning it and relaying it, the artificial turf is a manufactured material which has means provided thereon for anchoring it in position and attaching it to the laying apparatus and has sufficient strength that it can be pulled with considerable force without being torn apart. This, however, is not the case with sod which is held together entirely by the roots of the grass, which roots are a large portion of the sod.
There are machines that lay paper or similar strips on the ground, such as mulching strips, the paper coming in a roll on a spindle and having sufficient strength to be pulled from the spindle onto the ground on which it is laid by suitable rotational means. Among such paper strip laying means are some that have a ground engaging roller that deposits the strip on the ground and controls the feed of the strip from the roll, on which it comes from the manufacturer. Other materials than paper strips have also been used for a similar purpose such as rolls of foil. However, in all these devices the strips that are laid on the ground are uniform in width and thickness and of a length many times that of the sod lengths that are rolled up to make the rolls of sod. Because of the character of the material that is being laid, the action of actually laying the lengths of sod, on the surface on which the grass is to be grown, has to be done in such a way that no tendency to tear the length in two or more pieces will occur. The relatively short lengths of sod have to be fed to the laying apparatus in such a manner that the sod is not damaged thereby. In view of the necessity of keeping the lengths of sod in this condition, and because of the shortness of the individual lengths of sod, the apparatus that exists for laying paper strips, foil strips and artificial turf strips on the ground are not suitable for laying sod lengths on a surface such as ground which has been previously prepared for that purpose.
It is accordingly a purpose of our invention to provide a sod laying machine that can be and is preferably attached to a pulling vehicle such as a tractor, which machine has a frame which has means thereon for supporting, in end to end relation or axial adjacency to each other, a plurality of rolls of sod for rotation about their approximate axes. The exact location of the axes of the rolls will vary in accordance with the character of the sod that has been cut which may produce a variation in the thickness of the plies of the rolls. The means for providing for the rotation of the rolls of sod comprises a plurality of freely rotatable supporting members that engage the outer under side of the roll. The sod is rolled with the earth and root side outwardly and the grass side inwardly, the rotatable supporting members thus engaging the earth and root side of the length of sod.
It is a further purpose of our invention to provide means for laying the lengths of sod on the surface prepared for receiving the same, which means comprises pairs of conveyor belts that have spaced parallel runs between which lengths of sod are fed, which paired belts have the entrance ends for the lengths of sod spaced forwardly from the discharge ends thereof, and incline downwardly from the entrance end to the discharge end of each of said pair of conveyor belts. The result of this is that the lengths of sod which enter between the paired sod laying belts, with the dirt end root sides up, are turned over so that when they reach the discharge end of the paired belt conveyors, adjacent the surface onto which the sod is to be paid, the dirt and root side is down when deposited on that surface, and the grass side is up.
It is another purpose of our invention to provide means for transferring the lengths of sod from the rolls to the sod laying conveyors comprising rotatable feeding members that have cylindrical outer surfaces from which hard rubber fingers project that are provided with bent or obliquely extending end portions that engage with the outer surface of the roll of sod and operate so as to withdraw the sod from the roll into position between the pair of conveyor belts of a sod laying conveyor. Because of the fact that the lengths of sod in the rolls vary slightly in length or, in other words, are not precisely the same length, it is necessary to be able to manually move a length of sod that is being withdrawn from the roll so as to abut the leading end edge thereof against the trailing end edge of the length of sod that has been previously fed to the sod laying conveying means. In order to accomplish this the driving means for the sod laying conveyors and the members for feeding the sod lengths to the sod laying conveying means is of such a character that the feeding means can be moved independently of the conveying laying means for the lengths of sod.
The conveying means for the lengths of sod and the feeding means for the lengths of sod are driven by a rotatably mounted roller that is in engagement with the ground and is carried in depending relation by the frame of the sod laying machine. It is another purpose of our invention to provide such rotatable ground engaging means that is a roller of an elongated cylindrical character which is inflatable and which has a flexible outer engaging surface that engages the ground, the roller extending over the entire width of the machine. The ground engaging roller is adapted to engage the laid sod immediately after it has been laid so as to press the sod downwardly firmly into engagement with the surface that has been prepared for its reception.
It is another purpose of our invention to provide a ratchet driving means for the feeding means so that the feeding means can be normally operated by the driving means for the sod laying conveyors, but which permits the manual operation of the feeding means independently of the driving means for the sod laying conveyors, for the purpose of butting the end edge of a following length of sod against the end edge of a length of sod that preceded it into the laying conveyors.